the THREE-SEDED MERCURY, a genus of plants belonging to the monoeica monadelphia clas. The characters of this genus are the following.—Male flowers crowded above the female ones: The calyx is a three or four-leaved-perianthium, the leaflets roundish, concave, and equal: The corolla is wanting: The filamina have from 6 to 18 filaments, which are short, crowded, and connected at the base; the antherae are roundish.—Female flowers fewer, placed beneath, and received into a large divided involucrem: The calyx is a perianthium, consisting of three leaflets, which are concave, converging, small, and persistent: No corolla: The pistillum has a roundish germen; the styli are three, branchy, often triplicate, and long; the stigmata are simple: The pericarpium has a roundish trilobulated trilocular capsule, the valvules gaping two ways: The seeds are solitary, roundish, and large.—This genus ranks in the 38th natural order, Tricoccæ. There are five species, all natives of Virginia.